Optical imaging system

ABSTRACT

An optical imaging system includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens disposed in order from an object side, wherein TTL/(2*IMG HT)≤0.6 is satisfied, where TTL is a distance on an optical axis from an object-side surface of the first lens to an imaging plane of an image sensor, and IMG HT is half a diagonal length of the imaging plane of the image sensor.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No. 17/017,792 filed on Sep. 11, 2020, which claims the benefit under 35 USC 119(a) of Korean Patent Application No. 10-2020-0067933 filed on Jun. 4, 2020, in the Korean Intellectual Property Office, the entire disclosures of which are incorporated herein by reference for all purposes.

BACKGROUND 1. Field

The present disclosure relates to an optical imaging system.

2. Description of the Background

A portable terminal device may be designed to include a camera including an optical imaging system provided with a plurality of lenses to perform video calls and to image objects.

As increased functions of a camera may be desired in a portable terminal device, there has been increasing demand for a camera, used for a portable terminal device, having high resolution.

As a portable terminal device may be designed to have a reduced size, it may be required for a camera used for a portable terminal device to have a reduced size.

Thus, it may be necessary to develop an optical imaging system which has a reduced size and high resolution.

The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the disclosure.

SUMMARY

This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.

In one general aspect, an optical imaging system includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens disposed in order from an object side, wherein TTL/(2*IMG HT)≤0.6 is satisfied, where TTL is a distance on an optical axis from an object-side surface of the first lens to an imaging plane of an image sensor, and IMG HT is half a diagonal length of the imaging plane of the image sensor.

Conditional expression (v2+v3+v4+v5)/v1<2 may be satisfied, where v1 is an Abbe number of the first lens, v2 is an Abbe number of the second lens, v3 is an Abbe number of the third lens, v4 is an Abbe number of the fourth lens, and v5 is an Abbe number of the fifth lens.

Conditional expression 0<f1/f<1.8 may be satisfied, where f1 is a focal length of the first lens, and f is a focal length of the optical imaging system.

Conditional expression −4<f2/f<−1 may be satisfied, where f2 is a focal length of the second lens.

Conditional expression f3/f>3 may be satisfied, where f3 is a focal length of the third lens.

Conditional expression |f4/f|>3 may be satisfied, where f4 is a focal length of the fourth lens.

Conditional expression |f5/f1>5 may be satisfied, where f5 is a focal length of the fifth lens.

Conditional expression 0<f6/f<2 may be satisfied, where f6 is a focal length of the sixth lens.

Conditional expression −2<f7/f<0 may be satisfied, where f7 is a focal length of the seventh lens.

Conditional expression TTL/f<1.2 may be satisfied, and conditional expression BFL/f<0.3 may be satisfied, where BFL is a distance on the optical axis from an image-side surface of the seventh lens to the imaging plane of the image sensor.

Conditional expression |f1/f2|<1 may be satisfied.

Conditional expression −2<f2/f3<0 may be satisfied.

Conditional expression D1/f<0.1 may be satisfied, where D1 is a distance on the optical axis from an image-side surface of the first lens to an object-side surface of the second lens.

Conditional expression 84°<FOV<92° may be satisfied, where FOV is a field of view of the optical imaging system.

Conditional expression Fno<2.2 may be satisfied, where Fno is an F number of the optical imaging system.

Conditional expression 1<f12/f<2 may be satisfied, where f12 is a combined focal length of the first lens and the second lens.

The first lens may have positive refractive power, the second lens may have negative refractive power, the third lens may have positive refractive power, the fourth lens may have negative refractive power, the sixth lens may have positive refractive power, and the seventh lens may have negative refractive power.

Conditional expression 25<v1−v2<45 may be satisfied.

Conditional expression v1−v3<35 may be satisfied.

Conditional expression 15<v1−v5<25 may be satisfied.

Other features and aspects will be apparent from the following detailed description, the drawings, and the claims.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram illustrating a first example of an optical imaging system.

FIG. 2 is a diagram illustrating aberration properties of the optical imaging system illustrated in FIG. 1 .

FIG. 3 is a diagram illustrating a second example of an optical imaging system.

FIG. 4 is a diagram illustrating aberration properties of the optical imaging system illustrated in FIG. 3 .

FIG. 5 is a diagram illustrating a third example of an optical imaging system.

FIG. 6 is a diagram illustrating aberration properties of the optical imaging system illustrated in FIG. 5 .

FIG. 7 is a diagram illustrating a fourth example of an optical imaging system.

FIG. 8 is a diagram illustrating aberration properties of the optical imaging system illustrated in FIG. 7 .

FIG. 9 is a diagram illustrating a fifth example of an optical imaging system.

FIG. 10 is a diagram illustrating aberration properties of the optical imaging system illustrated in FIG. 9 .

Throughout the drawings and the detailed description, the same reference numerals refer to the same elements. The drawings may not be to scale, and the relative size, proportions, and depiction of elements in the drawings may be exaggerated for clarity, illustration, and convenience.

DETAILED DESCRIPTION

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings, it is noted that examples are not limited to the same.

The following detailed description is provided to assist the reader in gaining a comprehensive understanding of the methods, apparatuses, and/or systems described herein. However, various changes, modifications, and equivalents of the methods, apparatuses, and/or systems described herein will be apparent after an understanding of this disclosure. For example, the sequences of operations described herein are merely examples, and are not limited to those set forth herein, but may be changed as will be apparent after an understanding of this disclosure, with the exception of operations necessarily occurring in a certain order. Also, descriptions of features that are known in the art may be omitted for increased clarity and conciseness.

The features described herein may be embodied in different forms, and are not to be construed as being limited to the examples described herein. Rather, the examples described herein have been provided merely to illustrate some of the many possible ways of implementing the methods, apparatuses, and/or systems described herein that will be apparent after an understanding of this disclosure.

Throughout the specification, when an element, such as a layer, region, or substrate, is described as being “on,” “connected to,” or “coupled to” another element, it may be directly “on,” “connected to,” or “coupled to” the other element, or there may be one or more other elements intervening therebetween. In contrast, when an element is described as being “directly on,” “directly connected to,” or “directly coupled to” another element, there can be no other elements intervening therebetween. As used herein “portion” of an element may include the whole element or less than the whole element.

As used herein, the term “and/or” includes any one and any combination of any two or more of the associated listed items; likewise, “at least one of” includes any one and any combination of any two or more of the associated listed items.

Although terms such as “first,” “second,” and “third” may be used herein to describe various members, components, regions, layers, or sections, these members, components, regions, layers, or sections are not to be limited by these terms. Rather, these terms are only used to distinguish one member, component, region, layer, or section from another member, component, region, layer, or section. Thus, a first member, component, region, layer, or section referred to in examples described herein may also be referred to as a second member, component, region, layer, or section without departing from the teachings of the examples.

Spatially relative terms, such as “above,” “upper,” “below,” “lower,” and the like, may be used herein for ease of description to describe one element's relationship to another element as shown in the figures. Such spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, an element described as being “above,” or “upper” relative to another element would then be “below,” or “lower” relative to the other element. Thus, the term “above” encompasses both the above and below orientations depending on the spatial orientation of the device. The device may be also be oriented in other ways (rotated 90 degrees or at other orientations), and the spatially relative terms used herein are to be interpreted accordingly.

The terminology used herein is for describing various examples only, and is not to be used to limit the disclosure. The articles “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms, “includes,” “comprises,” “is configured to,” “has,” etc. of the description specify the presence of stated features, numbers, steps, operations, members, elements, parts, and/or combinations thereof, but do not preclude the presence or addition of one or more other features, numbers, steps, operations, members, elements, parts, and/or combinations thereof.

The features of the examples described herein may be combined in various ways as will be apparent after an understanding of this disclosure. Further, although the examples described herein have a variety of configurations, other configurations are possible as will be apparent after an understanding of this disclosure.

Due to manufacturing techniques and/or tolerances, variations of the shapes shown in the drawings may occur. Thus, the examples described herein are not limited to the specific shapes shown in the drawings, but include changes in shape that occur during manufacturing.

In the following lens configuration diagrams, a thickness, a size, and a shape of a lens may be illustrated in a somewhat exaggerated manner for explanatory purposes, for example, the shape of a spherical or an aspherical surface of a lens presented in the lens configuration diagram is illustrated by way of example only, and a shape is not limited thereto.

Herein, it is noted that use of the term “may” with respect to an example, for example, as to what an example may include or implement, means that at least one example exists in which such a feature is included or implemented while all examples are not limited thereto.

A first lens refers to a lens the most adjacent to an object side, and a seventh lens refers to a lens the most adjacent to an image sensor.

Also, a first surface (or an object-side surface) refers to a surface the most adjacent to an object side, and a second surface (or an image-side surface) refers to a surface the most adjacent to an image side. Also, a radius of curvature, a thickness, a distance, a focal length, or the like, of a lens are indicated in millimeters (mm), and a field of view (FOV) is indicated in degrees.

In the descriptions of a shape of a lens, the configuration in which one surface is convex indicates that a paraxial region of the surface is convex, the configuration in which one surface is concave indicates that a paraxial region of the surface is concave, and the configuration in which one surface is planar indicates that a paraxial region of the surface is planar. Thus, even when it is described that one surface of a lens is convex, an edge of the lens may be concave. Similarly, even when it is described that one surface of a lens is concave, an edge of the lens may be convex. Also, even when it is described that one surface of a lens is planar, an edge of the lens may be convex or concave.

A paraxial region refers to a narrow region proximate to an optical axis including the optical axis.

An aspect of the present disclosure is to provide an optical imaging system which may implement high resolution and may have a reduced size.

The optical imaging system in the example embodiments may include seven lenses.

For example, the optical imaging system in the example embodiments may include a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens disposed in order from an object side. The first to seventh lenses may be spaced apart from each other by a predetermined distance along an optical axis.

However, the optical imaging system in the example embodiments does not only include seven lenses, for example, the optical imaging system may further include other elements.

For example, the optical imaging system may further include an image sensor for converting an incident image of an object into an electrical signal.

Also, the optical imaging system may further include an infrared filter (hereinafter, referred to as a filter) for blocking infrared rays. A filter may be disposed between the seventh lens and an image sensor.

Also, the optical imaging system may further include a stop for adjusting the amount of light.

The first to seventh lenses included in the optical imaging system in the example embodiments may be formed of a plastic material.

Also, at least one of the first to seventh lenses may have an aspherical surface. Also, each of the first to seventh lenses may have at least one aspherical surface.

In other words, at least one of a first surface and a second surface of each of the first to seventh lenses may be aspherical. An aspherical surface of the first to seventh lenses may be expressed by Equation 1.

$\begin{matrix} {Z = {\frac{cY^{2}}{1 + \sqrt{1 - {\left( {1 + K} \right)c^{2}Y^{2}}}} + {AY}^{4} + {BY}^{6} + {CY}^{8} + {DY}^{10} + {EY}^{12} + {FY}^{14} + {GY}^{16} + {HY}^{18} + {JY}^{20} + {LY}^{22} + {MY}^{24} + {NY}^{26} + {OY}^{28} + {{PY}^{30}\ldots}}} & \left\lbrack {{Equation}1} \right\rbrack \end{matrix}$

In equation 1, “c” is a curvature of a lens (an inverse of a radius of a curvature), “k” is a conic constant, and “Y” is a distance from a certain point on an aspherical surface of the lens to an optical axis. “A to P” are aspheric constants, and “Z” is a distance from a certain point on an aspherical surface to an apex of the aspherical surface.

The optical imaging system including the first to seventh lenses may have positive refractive power, negative refractive power, positive refractive power, negative refractive power, positive refractive power, positive refractive power, and negative refractive power, respectively, or may have positive refractive power, negative refractive power, positive refractive power, negative refractive power, negative refractive power, positive refractive power, and negative refractive power, respectively.

The optical imaging system in the example embodiments may satisfy at least one of conditional expressions as below:

0<f1/f<1.8  [Conditional Expression 1]

25<v1−v2<45  [Conditional Expression 2]

v1−v3<35  [Conditional Expression 3]

15<v1−v5<25  [Conditional Expression 4]

(v2+v3+v4+v5)/v1<2  [Conditional Expression 5]

−4<f2/f<−1  [Conditional Expression 6]

f3/f>3  [Conditional Expression 7]

|f4/f|>3  [Conditional Expression 8]

|f5/f|>5  [Conditional Expression 9]

0<f6/f<2  [Conditional Expression 10]

−2<f7/f<0  [Conditional Expression 11]

TTL/f<1.2  [Conditional Expression 12]

|f1/f2|<1  [Conditional Expression 13]

−2<f2/f3<0  [Conditional Expression 14]

BFL/f<0.3  [Conditional Expression 15]

D1/f<0.1  [Conditional Expression 16]

84°<FOV<92°  [Conditional Expression 17]

Fno<2.2  [Conditional Expression 18]

TTL/(2*IMG HT)≤0.6  [Conditional Expression 19]

1<f12/f<2  [Conditional Expression 20]

In the conditional expressions, f is a total focal length of the optical imaging system, f1 is a focal length of the first lens, f2 is a focal length of the second lens, f3 is a focal length of the third lens, f4 is a focal length of the fourth lens, f5 is a focal length of the fifth lens, f6 is a focal length of the sixth lens, f7 is a focal length of the seventh lens, and f12 is a combined focal length of the first lens and the second lens.

v1 is an Abbe number of the first lens, v2 is an Abbe number of the second lens, v3 is an Abbe number of the third lens, and v5 is an Abbe number of the fifth lens.

TTL is a distance on an optical axis from an object-side surface of the first lens to an imaging plane of the image sensor, BFL is a distance on the optical axis from an image-side surface of the seventh lens to an imaging plane of the image sensor, D1 is a distance on an optical axis between an image-side surface of the first lens and an object-side surface of the second lens, and IMG HT is half a diagonal length of the imaging plane of the image sensor.

FOV is a field of view of an optical imaging system, and Fno is an (F-number) of the optical imaging system.

In the description below, the first to seventh lenses included in the optical imaging system of the example embodiments will be described.

The first lens may have positive refractive power. Also, the first lens may have a meniscus shape convex toward an object side. In other words, a first surface of the first lens may be convex, and a second surface of the first lens may be concave.

At least one of the first surface and the second surface of the first surface may be aspherical. For example, both surfaces of the first lens may be aspherical.

The second lens may have negative refractive power. Also, the second lens may have a meniscus shape convex toward an object side. In other words, the first surface of the second lens may be convex, and the second surface of the second lens may be concave.

At least one surface of the first surface and the second surface of the second lens may be aspherical. For example, both surfaces of the second lens may be aspherical.

The third lens may have positive refractive power. Also, both surfaces of the third lens may convex. In other words, the first and second surfaces of the third lens may be convex.

Alternatively, the third lens may have a meniscus shape convex toward an object side. In other words, the first surface of the third lens may be convex, and the second surface of the third lens may be concave.

At least one the first surface and the second surface of the third lens may be aspherical. For example, both surfaces of the third lens may be aspherical.

The fourth lens may have negative refractive power. Also, both surfaces of the fourth lens may be concave. In other words, the first surface and the second surface of the fourth lens may be concave.

At least one surface of the first lens and the second surface of the fourth lens may be aspherical. For example, both surfaces of the fourth lens may be aspherical.

The fifth lens may have positive or negative refractive power. Also, the fifth lens may have a meniscus shape convex toward an object side. In other words, the first surface of the fifth lens may be convex in a paraxial region, and the second surface of the fifth lens may be concave in a paraxial region.

At least one surface of the first surface and the second surface of the fifth lens may be aspherical. For example, both surfaces of the fifth lens may be aspherical.

The fifth lens may have at least one inflection point formed on at least one of the first surface and the second surface. For example, the first surface of the fifth lens may be convex in a paraxial region and may be concave in portions other than a paraxial region. The second surface of the fifth lens may be concave in a paraxial region, and may be convex in portions other than a paraxial region.

The sixth lens may have positive refractive power. Also, the sixth lens may have a meniscus shape convex toward an object side. In other words, the first surface of the sixth lens may be convex in a paraxial region, and the second surface may be concave in a paraxial region.

At least one surface of the first surface and the second surface of the sixth may be aspherical. For example, both surfaces of the sixth lens may be aspherical.

The sixth lens may have at least one inflection point formed on at least one of the first surface and the second surface. For example, the first surface of the sixth lens may be convex in a paraxial region and may be concave in portions other than a paraxial region. The second surface of the sixth lens may be concave in a paraxial region and may be convex in portions other than a paraxial region

The seventh lens may have negative refractive power. Also, both surfaces of the seventh lens may be concave. In other words, the first and second surfaces of the seventh lens may be concave in a paraxial region.

At least one surface of the first surface and the second surface may be aspherical. For example, both surfaces of the seventh lens may be aspherical.

At least one inflection point may be formed on at least one of the first and second surfaces of the seventh lens. For example, the first surface of the seventh lens may be concave in a paraxial region and may be convex in portions other than a paraxial region. The second surface of the seventh lens may be concave in a paraxial region and may be convex in portions other than a paraxial region.

The first lens and the second lens may be formed of plastic materials having different optical properties from each other, and the second lens and the third lens may be formed of plastic materials having different optical properties from each other. Also, the first to third lenses may be formed of plastic materials having different optical properties from each other.

Meanwhile, at least three of the first to seventh lenses may have a refractive index of greater than 1.64.

Also, at least two of the first to seventh lenses may have a refractive index of greater than 1.66.

Among the first to fourth lenses, a lens having negative refractive power may have a refractive index of greater than 1.66. For example, the second lens and the fourth lens may have negative refractive power and may have a refractive index of greater than 1.66.

Also, among the first to fourth lenses, a lens disposed between lenses having a refractive index of greater than 1.66 may have positive refractive power and may have a refractive index of greater than 1.64. For example, the third lens may have positive refractive power and a refractive index of greater than 1.64.

A first example of the optical imaging system will be described with reference to FIG. 1 .

The optical imaging system of the first example may include an optical system including a first lens 110, a second lens 120, a third lens 130, a fourth lens 140, a fifth lens 150, a sixth lens 160, and a seventh lens 170, and may further include a stop, a filter 180, and an image sensor 190.

Lens characteristics (a radius of curvature, a thickness of a lens or a distance between lenses, a refractive index, an Abbe number, and a focal length) of each lens are indicated in Table 1 below.

TABLE 1 Surface Radius of Refractive Abbe Focal No. Note Curvature Thickness or Distance Index Number Length S1 First Lens 2.29841 0.76239 1.547 56.1 5.58 S2 8.22112 0.11438 S3 Second 6.38617 0.21051 1.680 19.2 −14.45 S4 Lens 3.81806 0.46482 S5 Third Lens 25.87199 0.43025 1.642 23.9 31.85 S6 −96.68416 0.30698 S7 Fourth −65.14354 0.27550 1.680 19.2 −21.80 S8 Lens 19.20686 0.34914 S9 Fifth Lens 9.76229 0.37269 1.571 37.4 44.20 S10 15.69514 0.59161 S11 Sixth Lens 3.17056 0.46896 1.547 56.1 8.00 S12 10.95091 1.26839 S13 Seventh −9.64588 0.41100 1.547 56.1 −4.33 S14 Lens 3.17913 0.10832 S15 Filter Infinity 0.11000 1.519 64.2 S16 Infinity 0.72206 S17 Imaging Infinity Plane

A focal length f of the optical imaging system of the first example is 6.17 mm, f12 is 8.10 mm, Fno is 2.1, FOV is 86.8°, and IMG HT is 6 mm.

f12 is a combined focal length of the first lens and the second lens, Fno is a number representing brightness of the optical imaging system, FOV is a field of view of the optical imaging system, and IMG HT is half a diagonal length of an imaging plane of the image sensor.

In the first example, the first lens 110 may have positive refractive power, the first surface of the first lens 110 may be convex, and the second surface of the first lens 110 may be concave.

The second lens 120 may have negative refractive power, the first surface of the second lens 120 may be convex, and the second surface of the second lens 120 may be concave.

The third lens 130 may have positive refractive power, and the first and second surfaces of the third lens 130 may be convex.

The fourth lens 140 may have negative refractive power, and the first and second surfaces of the fourth lens 140 may be concave.

The fifth lens 150 may have positive refractive power, the first surface of the fifth lens 150 may be convex in a paraxial region, and the second surface of the fifth lens 150 may be concave in a paraxial region.

Also, at least one inflection point may be formed on at least one of the first and second surfaces of the fifth lens 150. For example, the first surface of the fifth lens 150 may be convex in a paraxial region and may be concave in portions other than a paraxial region. Further, the second surface of the fifth lens 150 may be concave in a paraxial region and may be convex in portions other than a paraxial region.

The sixth lens 160 may have a positive refractive power, the first surface of the sixth lens 160 may be convex in a paraxial region, and the second surface of the sixth lens 160 may be concave in a paraxial region.

At least one inflection point may be formed on at least one of the first and second surfaces of the sixth lens 160. For example, the first surface of the sixth lens 160 may be convex in a paraxial region and may be concave in portions other than a paraxial region. Further, the second surface of the sixth lens 160 may be concave in a paraxial region and may be convex in portions other than a paraxial region.

The seventh lens 170 may have negative refractive power, and the first and second surfaces of the seventh lens 170 may be concave in a paraxial region.

At least one inflection point may be formed on at least one of the first and second surfaces of the seventh lens 170. For example, the first surface of the seventh lens 170 may be concave in a paraxial region and may be convex in portions other than a paraxial region. Further, the second surface of the seventh lens 170 may be concave in a paraxial region and may be convex in portions other than a paraxial region.

Each surface of the first lens 110 to the seventh lens 170 may have an aspherical coefficient as in Table 2. For example, both an object-side surface and an image-side surface of each of the first lens 110 to the seventh lens 170 may be aspherical.

TABLE 2 S1 S2 S3 S4 S5 S6 S7 Conic Constant(K) −0.83 15.36 16.18 3.88 −95.00 99.00 99.00 Fourth Coefficient(A) −0.01 −0.06 −0.08 −0.07 0.00 0.02 0.04 Sixth 0.17 0.43 0.35 0.62 −0.12 −0.34 −0.49 Coefficient(B) Eighth −0.78 −3.03 −2.16 −4.74 0.60 1.83 1.86 Coefficient(C) Tenth 2.32 13.58 9.86 23.57 −1.95 −6.58 −4.69 Coefficient(D) Twelfth −4.74 −39.95 −30.68 −77.17 4.25 16.36 8.05 Coefficient(E) Fourteenth 6.88 80.55 66.65 173.86 −6.35 −28.77 −9.64 Coefficient(F) Sixteenth −7.21 −114.48 −103.41 −277.74 6.59 36.40 8.15 Coefficient(G) Eighteenth 5.53 116.48 115.99 319.76 −4.72 −33.39 −4.86 Coefficient(H) Twentieth −3.09 −85.17 −94.19 −266.37 2.26 22.20 2.00 Coefficient(J) Twenty Second 1.25 44.37 54.83 159.17 −0.66 −10.58 −0.54 Coefficient(L) Twenty Fourth −0.36 −16.06 −22.29 −66.52 0.08 3.51 0.08 Coefficient(M) Twenty Sixth 0.07 3.84 6.01 18.47 0.01 −0.77 0.00 Coefficient(N) Twenty Eighth Coefficient(O) −0.01 −0.54 −0.97 −3.06 −0.01 0.10 0.00 Thirtieth Coefficient(P) 0.00 0.03 0.07 0.23 0.00 −0.01 0.00 S8 S9 S10 S11 S12 S13 S14 Conic 93.86 13.88 −54.79 −6.27 −2.72 −3.31 −18.40 Constant(K) Fourth 0.00 −0.05 −0.07 0.02 0.05 −0.08 −0.05 Coefficient(A) Sixth −0.15 −0.01 0.01 −0.03 −0.03 0.05 0.02 Coefficient(B) Eighth 0.41 0.07 0.02 0.01 0.01 −0.02 −0.01 Coefficient(C) Tenth −0.76 −0.10 −0.02 −0.01 0.00 0.01 0.00 Coefficient(D) Twelfth 0.95 0.09 0.01 0.00 0.00 0.00 0.00 Coefficient(E) Fourteenth −0.83 −0.06 −0.01 0.00 0.00 0.00 0.00 Coefficient(F) Sixteenth 0.52 0.03 0.00 0.00 0.00 0.00 0.00 Coefficient(G) Eighteenth −0.23 −0.01 0.00 0.00 0.00 0.00 0.00 Coefficient(H) Twentieth 0.07 0.00 0.00 0.00 0.00 0.00 0.00 Coefficient(J) Twenty Second −0.01 0.00 0.00 0.00 0.00 0.00 0.00 Coefficient(L) Twenty Fourth 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Coefficient(M) Twenty Sixth 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Coefficient(N) Twenty Eighth 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Coefficient(O) Thirtieth 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Coefficient(P)

In addition, the optical imaging system as described in the first example above may have aberration characteristics as illustrated in FIG. 2 .

A second example of the optical imaging system will be described with reference to FIG. 3 .

The optical imaging system of the second example may include an optical system including a first lens 210, a second lens 220, a third lens 230, a fourth lens 240, a fifth lens 250, a sixth lens 260, and a seventh lens 270, and may further include a stop, a filter 280, and an image sensor 290.

Lens characteristics (a radius of curvature, a thickness of a lens or a distance between lenses, a refractive index, an Abbe number, and a focal length) of each lens are indicated in Table 3 below.

TABLE 3 Surface Radius of Refractive Abbe Focal No. Note Curvature Thickness or Distance Index Number Length S1 First Lens 2.28849 0.76330 1.547 56.1 5.55 S2 8.20854 0.11509 S3 Second 6.35935 0.21000 1.680 19.2 −14.36 S4 Lens 3.79882 0.45821 S5 Third Lens 26.99476 0.42935 1.642 23.9 31.63 S6 −81.29169 0.30492 S7 Fourth −64.86509 0.27801 1.680 19.2 −21.77 S8 Lens 19.19682 0.35142 S9 Fifth Lens 9.71006 0.37424 1.571 37.4 44.77 S10 15.43466 0.59445 S11 Sixth Lens 3.13158 0.48624 1.547 56.1 8.01 S12 10.38317 1.24176 S13 Seventh −9.93485 0.41013 1.547 56.1 −4.36 S14 Lens 3.17888 0.10286 S15 Filter Infinity 0.11000 1.519 64.2 S16 Infinity 0.72000 S17 Imaging Infinity Plane

A focal length f of the optical imaging system of the second example is 6.14 mm, f12 is 8.06 mm, Fno is 2.09, FOV is 86.9°, and IMG HT is 6 mm.

The definitions of f12, Fno, FOV, and IMG HT are as in the first example.

In the second example, the first lens 210 may have positive refractive power, the first surface of the first lens 210 may be convex, and the second surface of the first lens 210 may be concave.

The second lens 220 may have negative refractive power, the first surface of the second lens 220 may be convex, and the second surface of the second lens 220 may be concave.

The third lens 230 may have positive refractive power, and the first and second surfaces of the third lens 230 may be convex.

The fourth lens 240 may have negative refractive power, and the first and second surfaces of the fourth lens 240 may be concave.

The fifth lens 250 may have positive refractive power, the first surface of the fifth lens 250 may be convex in a paraxial region, and the second surface of the fifth lens 250 may be concave in a paraxial region.

Also, at least one inflection point may be formed on at least one of the first and second surfaces of the fifth lens 250. For example, the first surface of the fifth lens 250 may be convex in a paraxial region and may be concave in portions other than a paraxial region. Further, the second surface of the fifth lens 250 may be concave in a paraxial region and may be convex in portions other than a paraxial region.

The sixth lens 260 may have positive refractive power, the first surface of the sixth lens 260 may be convex in a paraxial region, and the second surface of the sixth lens 260 may be concave in a paraxial region.

At least one inflection point may be formed on at least one of the first and second surfaces of the sixth lens 260. For example, the first surface of the sixth lens 260 may be convex in a paraxial region and may be concave in portions other than a paraxial region. Further, the second surface of the sixth lens 260 may be concave in a paraxial region and may be convex in portions other than a paraxial region.

The seventh lens 270 may have negative refractive power, and the first and second surfaces of the seventh lens 270 may be concave in a paraxial region.

At least one inflection point may be formed on at least one of the first and second surfaces of the seventh lens 270. For example, the first surface of the seventh lens 270 may be concave in a paraxial region and may be convex in portions other than a paraxial region. Further, the second surface of the seventh lens 270 may be concave in a paraxial region and may be convex in portions other than a paraxial region.

Each surface of the first lens 210 to the seventh lens 270 may have an aspherical coefficient as in Table 4. For example, both an object-side surface and an image-side surface of each of the first lens 210 to the seventh lens 270 may be aspherical.

TABLE 4 S1 S2 S3 S4 S5 S6 S7 Conic −0.83 15.47 16.23 3.90 −94.97 99.00 99.00 Constant(K) Fourth −0.02 −0.07 −0.10 −0.07 0.00 0.02 0.04 Coefficient(A) Sixth 0.21 0.57 0.65 0.65 −0.17 −0.30 −0.49 Coefficient(B) Eighth −0.95 −3.65 −4.48 −4.94 0.99 1.42 1.90 Coefficient(C) Tenth 2.76 15.04 21.09 24.79 −3.83 −4.65 −4.94 Coefficient(D) Twelfth −5.39 −41.34 −67.10 −82.98 10.22 10.64 8.86 Coefficient(E) Fourteenth 7.28 78.79 148.90 192.85 −19.37 −17.45 −11.22 Coefficient(F) Sixteenth −6.96 −106.79 −235.74 −319.73 26.55 20.82 10.21 Coefficient(G) Eighteenth 4.75 104.35 269.41 383.55 −26.55 −18.19 −6.71 Coefficient(H) Twentieth −2.31 −73.67 −222.52 −333.80 19.35 11.61 3.17 Coefficient(J) Twenty Second 0.78 37.22 131.48 208.68 −10.14 −5.34 −1.05 Coefficient(L) Twenty Fourth −0.18 −13.11 −54.14 −91.31 3.72 1.72 0.24 Coefficient(M) Twenty Sixth 0.03 3.06 14.75 26.53 −0.91 −0.37 −0.03 Coefficient(N) Twenty Eighth Coefficient(O) 0.00 −0.42 −2.39 −4.60 0.13 0.05 0.00 Thirtieth 0.00 0.03 0.17 0.36 −0.01 0.00 0.00 Coefficient(P) S8 S9 S10 S11 S12 S13 S14 Conic 94.77 13.99 −58.84 −6.41 −8.72 −2.03 −17.14 Constant(K) Fourth 0.00 −0.05 −0.07 0.02 0.05 −0.09 −0.05 Coefficient(A) Sixth −0.15 −0.01 0.01 −0.03 −0.03 0.05 0.02 Coefficient(B) Eighth 0.37 0.06 0.02 0.02 0.01 −0.02 −0.01 Coefficient(C) Tenth −0.63 −0.07 −0.01 −0.01 0.00 0.01 0.00 Coefficient(D) Twelfth 0.71 0.06 0.00 0.00 0.00 0.00 0.00 Coefficient(E) Fourteenth −0.54 −0.03 0.00 0.00 0.00 0.00 0.00 Coefficient(F) Sixteenth 0.26 0.02 0.00 0.00 0.00 0.00 0.00 Coefficient(G) Eighteenth −0.07 −0.01 0.00 0.00 0.00 0.00 0.00 Coefficient(H) Twentieth 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Coefficient(J) Twenty Second 0.01 0.00 0.00 0.00 0.00 0.00 0.00 Coefficient(L) Twenty Fourth 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Coefficient(M) Twenty Sixth 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Coefficient(N) Twenty Eighth 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Coefficient(O) Thirtieth 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Coefficient(P)

In addition, the optical imaging system as described in the second example above may have aberration characteristics as illustrated in FIG. 4 .

A third example of the optical imaging system will be described with reference to FIG. 5 .

The optical imaging system of the third example may include an optical system including a first lens 310, a second lens 320, a third lens 330, a fourth lens 340, a fifth lens 350, a sixth lens 360, and a seventh lens 370, and may further include a stop, a filter 380, and an image sensor 390.

Lens characteristics (a radius of curvature, a thickness of a lens or a distance between lenses, a refractive index, an Abbe number, and a focal length) of each lens are indicated in Table 5 below.

TABLE 5 Surface Radius of Refractive Abbe Focal No. Note Curvature Thickness or Distance Index Number Length S1 First Lens 2.29153 0.77274 1.547 56.1 5.55 S2 8.23456 0.10919 S3 Second 6.40025 0.21000 1.680 19.2 −14.39 S4 Lens 3.81715 0.45841 S5 Third Lens 21.37334 0.41688 1.642 23.9 32.50 S6 −850.29506 0.32297 S7 Fourth −71.39633 0.28900 1.680 19.2 −22.37 S8 Lens 19.34188 0.35230 S9 Fifth Lens 9.74308 0.37428 1.571 37.4 56.83 S10 13.72711 0.57535 S11 Sixth Lens 3.08993 0.49707 1.547 56.1 7.65 S12 11.16346 1.23182 S13 Seventh −9.63838 0.41000 1.547 56.1 −4.28 S14 Lens 3.13516 0.10000 S15 Filter Infinity 0.11000 1.519 64.2 S16 Infinity 0.72000 S17 Imaging Infinity Plane

A focal length f of the optical imaging system of the third example is 6.14 mm, f12 is 8.05 mm, Fno is 2.07, FOV is 86.8°, and IMG HT is 6 mm.

The definitions of f12, Fno, FOV, and IMG HT are as in the first example.

In the third example, the first lens 310 may have positive refractive power, the first surface of the first lens 310 may be convex, and the second surface of the first lens 310 may be concave.

The second lens 320 may have negative refractive power, the first surface of the second lens 320 may be convex, and the second surface of the second lens 320 may be concave.

The third lens 330 may have positive refractive power, and the first and second surfaces of the third lens 330 may be convex.

The fourth lens 340 may have negative refractive power, and the first and second surfaces of the fourth lens 340 may be concave.

The fifth lens 350 may have positive refractive power, the first surface of the fifth lens 350 may be convex in a paraxial region, and the second surface of the fifth lens 350 may be concave in a paraxial region.

Also, at least one inflection point may be formed on at least one of the first and second surfaces of the fifth lens 350. For example, the first surface of the fifth lens 350 may be convex in a paraxial region and may be concave in portions other than a paraxial region. Further, the second surface of the fifth lens 350 may be concave in a paraxial region and may be convex in portions other than a paraxial region.

The sixth lens 360 may have positive refractive power, the first surface of the sixth lens 360 may be convex in a paraxial region, and the second surface of the sixth lens 360 may be concave in a paraxial region.

At least one inflection point may be formed on at least one of the first and second surfaces of the sixth lens 360. For example, the first surface of the sixth lens 360 may be convex in a paraxial region and may be concave in portions other than a paraxial region. Further, the second surface of the sixth lens 360 may be concave in a paraxial region and may be convex in portions other than a paraxial region.

The seventh lens 370 may have negative refractive power, and the first and second surfaces of the seventh lens 370 may be concave in a paraxial region.

At least one inflection point may be formed on at least one of the first and second surfaces of the seventh lens 370. For example, the first surface of the seventh lens 370 may be concave in a paraxial region and may be convex in portions other than a paraxial region. Further, the second surface of the seventh lens 370 may be concave in a paraxial region and may be convex in portions other than a paraxial region.

Each surface of the first lens 310 to the seventh lens 370 may have an aspherical coefficient as in Table 6. For example, both an object-side surface and an image-side surface of each of the first lens 310 to the seventh lens 370 may be aspherical.

TABLE 6 S1 S2 S3 S4 S5 S6 S7 Conic −0.83 15.73 16.24 3.84 −95.00 99.00 99.00 Constant(K) Fourth −0.02 −0.06 −0.08 −0.06 0.00 0.02 0.05 Coefficient(A) Sixth 0.19 0.42 0.37 0.42 −0.13 −0.35 −0.57 Coefficient(B) Eighth −0.86 −2.64 −2.22 −2.91 0.62 1.75 2.39 Coefficient(C) Tenth 2.44 10.93 9.87 13.81 −1.83 −5.90 −6.73 Coefficient(D) Twelfth −4.62 −30.18 −29.99 −43.57 3.53 13.71 13.05 Coefficient(E) Fourteenth 6.03 57.66 63.75 95.10 −4.40 −22.59 −17.95 Coefficient(F) Sixteenth −5.53 −78.21 −96.70 −147.94 3.22 26.84 17.85 Coefficient(G) Eighteenth 3.58 76.37 105.77 166.68 −0.71 −23.20 −12.95 Coefficient(H) Twentieth −1.62 −53.83 −83.48 −136.56 −1.11 14.57 6.85 Coefficient(J) Twenty Second 0.50 27.12 47.03 80.65 1.35 −6.57 −2.60 Coefficient(L) Twenty Fourth −0.10 −9.52 −18.42 −33.48 −0.75 2.07 0.69 Coefficient(M) Twenty Sixth 0.01 2.21 4.76 9.27 0.24 −0.43 −0.12 Coefficient(N) Twenty Eighth 0.00 −0.31 −0.73 −1.54 −0.04 0.05 0.01 Coefficient(O) Thirtieth 0.00 0.02 0.05 0.12 0.00 0.00 0.00 Coefficient(P) S8 S9 S10 S11 S12 S13 S14 Conic 95.22 13.62 −69.03 −6.30 −1.63 −1.29 −19.37 Constant(K) Fourth 0.00 −0.05 −0.08 0.02 0.04 −0.10 −0.06 Coefficient(A) Sixth −0.14 0.00 0.02 −0.02 −0.02 0.07 0.03 Coefficient(B) Eighth 0.38 0.04 0.00 0.01 0.00 −0.03 −0.01 Coefficient(C) Tenth −0.70 −0.06 0.00 0.00 0.00 0.01 0.00 Coefficient(D) Twelfth 0.90 0.05 0.00 0.00 0.00 0.00 0.00 Coefficient(E) Fourteenth −0.82 −0.03 0.00 0.00 0.00 0.00 0.00 Coefficient(F) Sixteenth 0.53 0.02 0.00 0.00 0.00 0.00 0.00 Coefficient(G) Eighteenth −0.25 −0.01 0.00 0.00 0.00 0.00 0.00 Coefficient(H) Twentieth 0.08 0.00 0.00 0.00 0.00 0.00 0.00 Coefficient(J) Twenty Second −0.02 0.00 0.00 0.00 0.00 0.00 0.00 Coefficient(L) Twenty Fourth 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Coefficient(M) Twenty Sixth 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Coefficient(N) Twenty Eighth Coefficient(O) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Thirtieth 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Coefficient(P)

In addition, the optical imaging system as described in the third example above may have aberration characteristics as illustrated in FIG. 6 .

A fourth example of the optical imaging system will be described with reference to FIG. 7 .

The optical imaging system of the fourth example may include an optical system including a first lens 410, a second lens 420, a third lens 430, a fourth lens 440, a fifth lens 450, a sixth lens 460, and a seventh lens 470, and may further include a stop, a filter 480, and an image sensor 490.

Lens characteristics (a radius of curvature, a thickness of a lens or a distance between lenses, a refractive index, an Abbe number, and a focal length) of each lens are indicated in Table 7 below.

TABLE 7 Surface Radius of Refractive Abbe Focal No. Note Curvature Thickness or Distance Index Number Length S1 First Lens 2.30304 0.76509 1.547 56.1 5.55 S2 8.42496 0.09930 S3 Second 6.28862 0.21000 1.680 19.2 −15.01 S4 Lens 3.83778 0.46488 S5 Third Lens 25.14324 0.39999 1.642 23.9 35.89 S6 −272.70980 0.34005 S7 Fourth −82.16734 0.27969 1.680 19.2 −22.63 S8 Lens 18.94624 0.37621 S9 Fifth Lens 9.98619 0.37957 1.571 37.4 90.92 S10 12.19270 0.56739 S11 Sixth Lens 2.96631 0.56695 1.547 56.1 6.98 S12 12.41193 1.15413 S13 Seventh −10.27520 0.41000 1.547 56.1 −4.15 S14 Lens 2.94704 0.10675 S15 Filter Infinity 0.11000 1.519 64.2 S16 Infinity 0.72000 S17 Imaging Infinity Plane

A focal length f of the optical imaging system of the fourth example is 6.09 mm, f12 is 7.91 mm, Fno is 7.91, FOV is 87.3°, and IMG HT is 6 mm.

The definitions of f12, Fno, FOV, and IMG HT are as in the first example.

In the fourth example, the first lens 410 may have positive refractive power, the first surface of the first lens 410 may be convex, and the second surface of the first lens 410 may be concave.

The second lens 420 may have negative refractive power, the first surface of the second lens 420 may be convex, and the second surface of the second lens 420 may be concave.

The third lens 430 may have positive refractive power, and the first and second surfaces of the third lens 430 may be convex.

The fourth lens 440 may have negative refractive power, and the first and second surfaces of the fourth lens 440 may be concave.

The fifth lens 450 may have positive refractive power, the first surface of the fifth lens 450 may be convex in a paraxial region, and the second surface of the fifth lens 450 may be concave in a paraxial region.

Also, at least one inflection point may be formed on at least one of the first and second surfaces of the fifth lens 450. For example, the first surface of the fifth lens 450 may be convex in a paraxial region and may be concave in portions other than a paraxial region. Further, the second surface of the fifth lens 450 may be concave in a paraxial region and may be convex in portions other than a paraxial region.

The sixth lens 460 may have positive refractive power, the first surface of the sixth lens 460 may be convex in a paraxial region, and the second surface of the sixth lens 460 may be concave in a paraxial region.

At least one inflection point may be formed on at least one of the first and second surfaces of the sixth lens 460. For example, the first surface of the sixth lens 460 may be convex in a paraxial region and may be concave in portions other than a paraxial region. Further, the second surface of the sixth lens 460 may be concave in a paraxial region and may be convex in portions other than a paraxial region.

The seventh lens 470 may have negative refractive power, and the first and second surfaces of the seventh lens 470 may be concave in a paraxial region.

At least one inflection point may be formed on at least one of the first and second surfaces of the seventh lens 470. For example, the first surface of the seventh lens 470 may be concave in a paraxial region and may be convex in portions other than a paraxial region. Further, the second surface of the seventh lens 470 may be concave in a paraxial region and may be convex in portions other than a paraxial region.

Each surface of the first lens 410 to the seventh lens 470 may have an aspherical coefficient as in Table 8. For example, both an object-side surface and an image-side surface of each of the first lens 410 to the seventh lens 470 may be aspherical.

TABLE 8 S1 S2 S3 S4 S5 S6 S7 Conic −0.86 15.41 16.23 3.99 −95.00 99.00 99.00 Constant(K) Fourth 0.00 −0.07 −0.09 −0.04 0.00 0.01 0.04 Coefficient(A) Sixth 0.09 0.46 0.56 0.24 −0.10 −0.26 −0.54 Coefficient(B) Eighth −0.31 −2.77 −3.80 −1.59 0.39 1.29 2.33 Coefficient(C) Tenth 0.55 10.87 18.01 7.30 −0.94 −4.36 −6.72 Coefficient(D) Twelfth −0.24 −28.35 −57.75 −21.68 1.19 10.15 13.23 Coefficient(E) Fourteenth −1.09 51.00 128.96 43.19 −0.11 −16.70 −18.37 Coefficient(F) Sixteenth 2.81 −65.00 −204.95 −59.13 −2.31 19.76 18.32 Coefficient(G) Eighteenth −3.52 59.54 234.46 56.03 4.36 −16.97 −13.24 Coefficient(H) Twentieth 2.77 −39.31 −193.35 −36.29 −4.41 10.55 6.92 Coefficient(J) Twenty Second −1.46 18.54 113.76 15.38 2.84 −4.70 −2.58 Coefficient(L) Twenty Fourth 0.51 −6.09 −46.53 −3.79 −1.20 1.45 0.66 Coefficient(M) Twenty Sixth −0.12 1.32 12.56 0.33 0.32 −0.30 −0.11 Coefficient(N) Twenty Eighth 0.02 −0.17 −2.01 0.06 −0.05 0.04 0.01 Coefficient(O) Thirtieth 0.00 0.01 0.14 −0.01 0.00 0.00 0.00 Coefficient(P) S8 S9 S10 S11 S12 S13 S14 Conic 92.99 14.34 −88.58 −6.39 −2.06 −0.83 −21.99 Constant(K) Fourth −0.01 −0.06 −0.09 0.01 0.04 −0.11 −0.05 Coefficient(A) Sixth −0.15 0.01 0.03 −0.01 0.00 0.08 0.03 Coefficient(B) Eighth 0.49 0.03 0.01 0.00 −0.01 −0.04 −0.01 Coefficient(C) Tenth −1.03 −0.06 −0.02 0.00 0.01 0.01 0.00 Coefficient(D) Twelfth 1.51 0.04 0.02 0.00 0.00 0.00 0.00 Coefficient(E) Fourteenth −1.57 −0.02 −0.01 0.00 0.00 0.00 0.00 Coefficient(F) Sixteenth 1.19 0.01 0.00 0.00 0.00 0.00 0.00 Coefficient(G) Eighteenth −0.66 0.00 0.00 0.00 0.00 0.00 0.00 Coefficient(H) Twentieth 0.27 0.00 0.00 0.00 0.00 0.00 0.00 Coefficient(J) Twenty Second Coefficient(L) −0.08 0.00 0.00 0.00 0.00 0.00 0.00 Twenty Fourth 0.02 0.00 0.00 0.00 0.00 0.00 0.00 Coefficient(M) Twenty Sixth 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Coefficient(N) Twenty Eighth 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Coefficient(O) Thirtieth 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Coefficient(P)

In addition, the optical imaging system as described in the fourth example above may have aberration characteristics as illustrated in FIG. 8 .

A fifth example of the optical imaging system will be described with reference to FIG. 9 .

The optical imaging system of the fifth example may include an optical system including a first lens 510, a second lens 520, a third lens 530, a fourth lens 540, a fifth lens 550, a sixth lens 560, and a seventh lens 570, and may further include a stop, a filter 580, and an image sensor 590.

Lens characteristics (a radius of curvature, a thickness of a lens or a distance between lenses, a refractive index, an Abbe number, and a focal length) of each lens are indicated in Table 9 below.

TABLE 9 Surface Radius of Refractive Abbe Focal No. Note Curvature Thickness or Distance Index Number Length S1 First Lens 2.34050 0.74555 1.547 56.1 5.62 S2 8.72464 0.10851 S3 Second 6.73780 0.21000 1.680 19.2 −15.33 S4 Lens 4.04021 0.46098 S5 Third Lens 18.53728 0.38427 1.642 23.9 30.52 S6 343.70020 0.34399 S7 Fourth −57.20565 0.27000 1.680 19.2 −20.73 S8 Lens 18.72890 0.38351 S9 Fifth Lens 10.17700 0.41037 1.571 37.4 −215.82 S10 9.26311 0.53719 S11 Sixth Lens 2.77358 0.67928 1.547 56.1 6.23 S12 13.64237 1.09911 S13 Seventh −10.91942 0.41000 1.547 56.1 −4.40 S14 Lens 3.12607 0.12724 S15 Filter Infinity 0.11000 1.519 64.2 S16 Infinity 0.72000 S17 Imaging Infinity Plane

A focal length f of the optical imaging system of the fifth example is 6.01 mm, f12 is 8 mm, Fno is 2.06, FOV is 88°, and IMG HT is 6 mm.

The definitions of f12, Fno, FOV, and IMG HT are as in the first example.

In the fifth example, the first lens 510 may have positive refractive power, the first surface of the first lens 510 may be convex, and the second surface of the first lens 510 may be concave.

The second lens 520 may have negative refractive power, the first surface of the second lens 520 may be convex, and the second surface of the second lens 520 may be concave.

The third lens 530 may have positive refractive power, and the first surface of the third lens 530 may be convex, and the second surface of the third lens 530 may be concave.

The fourth lens 540 may have negative refractive power, and the first and second surfaces of the fourth lens 540 may be concave.

The fifth lens 550 may have negative refractive power, the first surface of the fifth lens 550 may be convex in a paraxial region, and the second surface of the fifth lens 550 may be concave in a paraxial region.

Also, at least one inflection point may be formed on at least one of the first and second surfaces of the fifth lens 550. For example, the first surface of the fifth lens 550 may be convex in a paraxial region and may be concave in portions other than a paraxial region. Further, the second surface of the fifth lens 550 may be concave in a paraxial region and may be convex in portions other than a paraxial region.

The sixth lens 560 may have positive refractive power, the first surface of the sixth lens 560 may be convex in a paraxial region, and the second surface of the sixth lens 560 may be concave in a paraxial region.

At least one inflection point may be formed on at least one of the first and second surfaces of the sixth lens 560. For example, the first surface of the sixth lens 560 may be convex in a paraxial region and may be concave in portions other than a paraxial region. Further, the second surface of the sixth lens 560 may be concave in a paraxial region and may be convex in portions other than a paraxial region.

The seventh lens 570 may have negative refractive power, and the first and second surfaces of the seventh lens 570 may be concave in a paraxial region.

At least one inflection point may be formed on at least one of the first and second surfaces of the seventh lens 570. For example, the first surface of the seventh lens 570 may be concave in a paraxial region and may be convex in portions other than a paraxial region. Further, the second surface of the seventh lens 570 may be concave in a paraxial region and may be convex in portions other than a paraxial region.

Each surface of the first lens 510 to the seventh lens 570 may have an aspherical coefficient as in Table 10. For example, both an object-side surface and an image-side surface of each of the first lens 510 to the seventh lens 570 may be aspherical.

TABLE 10 S1 S2 S3 S4 S5 S6 S7 Conic −0.90 17.11 16.33 3.48 −94.71 99.00 99.00 Constant(K) Fourth −0.02 −0.02 −0.04 −0.04 0.01 −0.02 0.02 Coefficient(A) Sixth 0.20 0.01 −0.10 0.17 −0.15 0.04 −0.37 Coefficient(B) Eighth −0.86 −0.36 1.12 −1.05 0.72 −0.16 1.69 Coefficient(C) Tenth 2.46 2.59 −5.83 4.16 −2.30 0.08 −5.10 Coefficient(D) Twelfth −4.70 −9.42 20.21 −9.55 5.03 1.09 10.34 Coefficient(E) Fourteenth 6.16 21.62 −48.43 11.74 −7.65 −4.09 −14.55 Coefficient(F) Sixteenth −5.52 −33.77 82.17 −3.12 8.23 7.66 14.54 Coefficient(G) Eighteenth 3.31 37.11 −100.08 −13.80 −6.31 −9.07 −10.42 Coefficient(H) Twentieth −1.23 −29.02 87.76 25.13 3.43 7.23 5.34 Coefficient(J) Twenty Second 0.20 16.07 −54.90 −22.53 −1.30 −3.95 −1.93 Coefficient(L) Twenty Fourth 0.04 −6.15 23.90 12.26 0.33 1.46 0.47 Coefficient(M) Twenty Sixth −0.03 1.55 −6.87 −4.11 −0.05 −0.35 −0.07 Coefficient(N) Twenty Eighth 0.01 −0.23 1.17 0.78 0.00 0.05 0.01 Coefficient(O) Thirtieth 0.00 0.02 −0.09 −0.07 0.00 0.00 0.00 Coefficient(P) S8 S9 S10 S11 S12 S13 S14 Conic 91.17 13.47 −95.64 −6.89 −5.00 −0.96 −20.11 Constant(K) Fourth −0.03 −0.08 −0.10 0.01 0.04 −0.06 −0.02 Coefficient(A) Sixth −0.01 0.06 0.08 −0.01 −0.02 0.02 0.00 Coefficient(B) Eighth 0.02 −0.03 −0.06 0.00 0.00 −0.01 0.00 Coefficient(C) Tenth −0.05 −0.02 0.04 0.00 0.00 0.00 0.00 Coefficient(D) Twelfth 0.09 0.06 −0.02 0.00 0.00 0.00 0.00 Coefficient(E) Fourteenth −0.09 −0.05 0.01 0.00 0.00 0.00 0.00 Coefficient(F) Sixteenth 0.05 0.03 0.00 0.00 0.00 0.00 0.00 Coefficient(G) Eighteenth −0.01 −0.01 0.00 0.00 0.00 0.00 0.00 Coefficient(H) Twentieth 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Coefficient(J) Twenty Second Coefficient(L) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Twenty Fourth 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Coefficient(M) Twenty Sixth 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Coefficient(N) Twenty Eighth 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Coefficient(O) Thirtieth 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Coefficient(P)

In addition, the optical imaging system as described in the fifth example above may have aberration characteristics as illustrated in FIG. 10 .

Table 11 lists values of conditional expressions of the optical imaging system for the first through fifth examples.

TABLE 11 First Second Third Fourth Fifth Conditional Expressions Example Example Example Example Example 0 < f1/f < 1.8 0.904 0.904 0.904 0.911 0.935 25 < v1-v2 < 45 36.9 36.9 36.9 36.9 36.9 v1-v3 < 35 32.2 32.2 32.2 32.2 32.2 15 < v1-v5 < 25 18.7 18.7 18.7 18.7 18.7 (v2 + v3 + v4 + v5)/v1 < 2 1.777 1.777 1.777 1.777 1.777 −4 < f2/f < −1 −2.342 −2.339 −2.344 −2.465 −2.551 f3/f > 3 5.162 5.151 5.293 5.893 5.078 |f4/f| > 3 3.533 3.546 3.643 3.716 3.449 |f5/f| > 5 7.164 7.292 9.256 14.929 35.910 0 < f6/f < 2 1.297 1.305 1.246 1.146 1.037 −2 < f7/f < 0 −0.702 −0.710 −0.697 −0.681 −0.732 TTL/f < 1.2 1.129 1.132 1.132 1.141 1.165 |f1/f2| < 1 0.386 0.386 0.386 0.370 0.367 −2 < f2/f3 < 0 −0.454 −0.454 −0.443 −0.418 −0.502 BFL/f < 0.3 0.152 0.152 0.151 0.154 0.159 D1/f < 0.1 0.019 0.019 0.018 0.016 0.018 84° < FOV < 92° 86.8 86.9 86.8 87.3 88.0 Fno < 2.2 2.10 2.09 2.07 2.08 2.06 TTL/(2*IMG HT) ≤ 0.6 0.581 0.579 0.579 0.579 0.583 1 < f12/f < 2 1.313 1.313 1.311 1.299 1.331

According to the aforementioned example embodiments, the optical imaging system may implement high resolution and may have a reduced size.

While specific examples have been shown and described above, it will be apparent after an understanding of this disclosure that various changes in form and details may be made in these examples without departing from the spirit and scope of the claims and their equivalents. The examples described herein are to be considered in a descriptive sense only, and not for purposes of limitation. Descriptions of features or aspects in each example are to be considered as being applicable to similar features or aspects in other examples. Suitable results may be achieved if the described techniques are performed in a different order, and/or if components in a described system, architecture, device, or circuit are combined in a different manner, and/or replaced or supplemented by other components or their equivalents. Therefore, the scope of the disclosure is defined not by the detailed description, but by the claims and their equivalents, and all variations within the scope of the claims and their equivalents are to be construed as being included in the disclosure. 

What is claimed is:
 1. An optical imaging system comprising: a first lens has positive refractive power, a convex object-side surface and a concave image-side surface; a second lens has negative refractive power, a convex object-side surface and a concave image-side surface; a third lens has positive refractive power; a fourth lens has negative refractive power and a concave image-side surface; a fifth lens has refractive power; a sixth lens has refractive power, a convex object-side surface and a concave image-side surface; and a seventh lens has negative refractive power, wherein the first to seventh lenses are disposed sequentially from an object side, wherein the optical imaging system has a total of seven lenses, wherein 0<f1/f<1.8, −4<f2/f<−1 and |f4/f|>3 are satisfied, where f1 is a focal length of the first lens, f2 is a focal length of the second lens, f4 is a focal length of the fourth lens, and f is a focal length of the optical imaging system.
 2. The optical imaging system of claim 1, wherein 1<f12/f<2 is satisfied, where f12 is a combined focal length of the first lens and the second lens.
 3. The optical imaging system of claim 1, wherein |f1/f2|<1 is satisfied.
 4. The optical imaging system of claim 1, wherein −2<f2/f3<0 is satisfied, where f3 is a focal length of the third lens.
 5. The optical imaging system of claim 4, wherein f3/f>3 is satisfied.
 6. The optical imaging system of claim 1, wherein −2<f7/f<0 is satisfied, where f7 is a focal length of the seventh lens.
 7. The optical imaging system of claim 1, wherein 25<v1−v2<45 is satisfied where v1 is an Abbe number of the first lens, and v2 is an Abbe number of the second lens.
 8. The optical imaging system of claim 7, wherein v1−v3<35 is satisfied where v3 is an Abbe number of the third lens.
 9. The optical imaging system of claim 1, wherein D1/f<0.1 is satisfied, where D1 is a distance on an optical axis from the image-side surface of the first lens to the object-side surface of the second lens.
 10. The optical imaging system of claim 1, wherein BFL/f<0.3 is satisfied, where BFL is a distance on an optical axis from an image-side surface of the seventh lens to an imaging plane.
 11. The optical imaging system of claim 1, wherein the third lens has a convex object-side surface.
 12. The optical imaging system of claim 11, wherein the third lens has a convex image-side surface.
 13. The optical imaging system of claim 1, wherein the fourth lens has a concave object-side surface.
 14. The optical imaging system of claim 1, wherein the fifth lens has positive refractive power.
 15. The optical imaging system of claim 1, wherein the seventh lens has a concave image-side surface.
 16. The optical imaging system of claim 1, wherein at least three of the first to seventh lenses have a refractive index of greater than 1.64.
 17. The optical imaging system of claim 1, wherein at least two of the first to seventh lenses have a refractive index of greater than 1.66.
 18. The optical imaging system of claim 17, wherein the second lens and the fourth lens have a refractive index of greater than 1.66. 